PHP实现计算抽奖概率算法

<?php

 //计算抽奖的概率

 function get_rand($proArr) {

 $result = '';

 $proSum = array_sum($proArr);

 foreach ($proArr as $key => $proCur) {

  $randNum = mt_rand(1, $proSum);

  if ($randNum <= $proCur) {

  $result = $key;

  break;

  } else {

  $proSum -= $proCur;

  }

 }

 unset ($proArr);

 return $result;

 }

 $prize_arr = array(

 '0' => array('id'=>1,'prize'=>'家电','v'=>2),

 '1' => array('id'=>2,'prize'=>'数码相机','v'=>5),

 '2' => array('id'=>3,'prize'=>'iPad','v'=>13),

 '3' => array('id'=>4,'prize'=>'LED显示器','v'=>15),

 '4' => array('id'=>5,'prize'=>'U盘','v'=>25),

 '5' => array('id'=>6,'prize'=>'键盘','v'=>30),

 '6' => array('id'=>7,'prize'=>'鼠标垫','v'=>10),

 );

 foreach ($prize_arr as $key => $val) {

 $arr[$val['id']] = $val['v'];

 }

 $rid = get_rand($arr);

 $res['yes'] = $prize_arr[$rid-1]['prize'];

 unset($prize_arr[$rid-1]);

 shuffle($prize_arr);

 $prize_arrcount = count($prize_arr);

 for($i=0;$i<$prize_arrcount;$i++){

 $pr[] = $prize_arr[$i]['prize'];

 }

 $res['no'] = $pr;

 //抽奖结果

 $ro = $res['yes'];

 print_r($ro);

?>

iPad